Dual-band Slot Antenna Research Articles

Optimization Assisted by Neural Network-Based Machine Learning in Electromagnetic Applications

We introduce an optimization assisted by a neural network (ONN) predictor to the electromagnetic community. ONN belongs to the class of the surrogate model-based optimization approaches, and approximates the objective function using a non-linear approximator – neural network. We provide a comprehensive description of the ONN algorithm and the details of its mathematical formulations. We apply ONN to optimize three popular benchmark functions and compare its performance with some commonly used optimization algorithms, namely particle swarm optimization, genetic algorithm, and Bayesian optimization. For the first time, we demonstrate ONN’s applicability and effectiveness in antenna design problems by optimizing a six-element Yagi-Uda antenna and by solving a challenging ten-dimensional dual-band slotted patch antenna constrained optimization problem. To achieve this, ONN is linked with a full-wave electromagnetic simulation solver through an application user interface. The optimized slotted patch is fabricated and measured to demonstrate how ONN can be part of the full antenna design process. Our empirical results indicate that ONN requires less objective function evaluations to reach the same qualitative point and reaches better optimal points for the same number of iterations for the studied benchmark functions and antenna optimization problems compared to the aforementioned baseline optimization algorithms.

A dual-band low-profile Fabry–Perot resonator antenna with single partially reflecting surface

ABSTRACTThis paper presents a novel design for a low-profile Fabry–Perot resonator antenna (FPRA) that operates at two distinct frequency bands using a single partially reflecting surface (PRS). The PRS is composed of two different types of unit cells arranged in a staggered fashion. These unit cells are comprised of double-sided complementary structures, including a square patch with a square aperture and a circular ring with a circular ring slot. To reduce the overall profile of the antenna, an artificial magnetic conductor (AMC) surface is utilized as the reflection plane. The proposed design employs a dual-band slotted patch antenna as the primary source. The overall dimensions of the FPRA are 91 mm×91 mm×5.54 mm. The performance of the prototype antenna is validated through measurement, demonstrating peak gains of 14.1 and 16.1 dBi at frequencies of 6.65 and 12.05 GHz, respectively. Additionally, the antenna exhibits −10 dB impedance bandwidths of 6.5–6.8 GHz and 12.15–12.23 GHz at the two frequency bands.

AMC-Based Low-Profile Dual-Band Slotted Patch Antenna for IoT Devices in the Healthcare System

An artificial magnetic conductor (AMC)-based patch antenna with a low profile is developed for wireless devices in IoT-based healthcare systems. The proposed antenna comprises two pairs of circular-shaped patches with circular-shaped slots and a dual-band 4 × 4 array of AMC reflectors with two zero-degree reflection responses to enhance the antenna's radiation performance. For the 2.45 GHz ISM and 5.4 GHz WLAN bands, the patch antenna has dimensions of 0.44λ0 × 0.52λ0 × 0.013λ0, with partial ground structures to improve radiation characteristics. Following that, a unique dual-band symmetrical AMC unit cell with dimensions of 22 × 22 × 1.6 mm3 is developed. There is a gap of 15 mm between the antenna and the AMC surface. The antenna is supported by a 4 × 4 AMC array that has a total dimension of 0.72λ0 × 0.72λ0 × 0.15λ0. The reflection coefficient values of less than − 10 dB in the 1.7–2.5 and 5.1–5.6 GHz bands, with a bandwidth percentage of 38 and 9.3%, respectively. The antenna's gains were 7.2 and 4 dBi inside the bands. Furthermore, the Specific Absorption Rate (SAR) value did not match the WHO's safety and health guidelines. The issue was solved by including an AMC surface in the proposed antenna. At 2.45 and 5.4 GHz, SAR values of 0.58 and 1.04 W/Kg were measured. Vector network analyser and anechoic chamber were used to test the performance of antenna and AMC surface prototypes. There is a substantial agreement among measured and simulated parameters of an antenna. Consequently, the developed antenna combination with the AMC structure is suited for wireless devices in ISM and WLAN bands, often used in IoT-based healthcare systems.

Multiple-input multiple-output dual-band dual-circularly polarised SIW cavity-backed slot antenna for satellite and 5G systems

ABSTRACT A dual-band 2 1 multiple-input-multiple-output (MIMO) antenna based on substrate integrated waveguide (SIW) cavity for both satellite (in K-band) and 5 G applications is proposed. Initially, the SIW cavity consisting of metallic vias on all four sides is implemented. For MIMO configuration, this cavity is divided into two smaller SIW cavities using a row of metallic vias and excited using the coaxial feed. By etching an asymmetric cross-slot (AXS) with tuned dimensions on top of the SIW cavity, a dualsense of circular polarisation (CP) in both frequency bands is obtained. The fabricated prototype of the proposed SIW antenna shows impedance bandwidth (IBW) of 15.36% (22.60–26.36 GHz; BandI) and 4.64% (29.04–30.42 GHz; BandII). The completely overlapping axial-ratio bandwidth (ARBW) with IBW of 15.16% (22.62–26.33 GHz) and 3.10% (29.20–30.12 GHz) with a peak gain of 12.47 and 7.71 dBi is obtained in BandI and Band II, respectively. The proposed antenna shows front-to-back ratio (FBR) of more than 20 dB in both resonating frequency bands. The measured results of the proposed MIMO antenna agree well with the simulation.

Substrate Integrated Waveguide Antenna at Millimeter Wave for 5G Application

This paper presents a dual-band slot antenna using substrate integrated waveguide (SIW) technology at 26 and 28 GHz. High loss is one of the main challenges faced by 5G base station network due to the severe path loss at high frequency. Hence, high gain antennas are required for 5G base station applications to overcome path loss issue. Hence, this work designs a high gain SIW antenna based on slot technology to excite dual-bands with high gain capability. The antenna is designed with two slots shaped to resonate at two different frequencies: 26 and 28 GHz. The antenna is analyzed using CST software and fabricated on Roger RT5880 substrate with permittivity of 2.2 and lost tangent of 0.0009 with thickness of 0.508 mm. The design operates at 26 and 28 GHz with measured reflection coefficients less than -10 dB. Measured high gains of 8 and 8.02 dB are obtained at 26 and 28 GHz, respectively. Overall, the antenna showed good performance that would benefit the fifth-generation applications.

Design of dual band slotted reconfigurable antenna using electronic switching circuit

This paper proposes a dual band reconfigurable microstrip slotted antenna for supporting the wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications, providing coverage where both directive and omni-directive radiations are needed. The design consists of a feedline, a ground plane with two slots and two gaps between them to provide the switching capability and a 1.6 mm thick flame retardant 4 (FR4) substrate (dielectric constant Ɛ=4.3, loss tangent δ=0.019), modeling an antenna size of 30x35x1.6 mm3. The EM simulation, which was carried out using the connected speech test (CST) studio suite 2017, generated dual wide bands of 40% (2-3 GHz) with -55 dB of S11 and 24% (5.2-6.6 GHz) higher than its predecessors with lower complexity and -60 dB of S11 in addition to the radiation pattern versatility while maintaining lower power consumption. Moreover, the antenna produced omnidirectional radiation patterns with over than 40% bandwith at 2.4 GHz and directional radiation patterns with 24% bandwith at the 5.8 GHz band. Furthermore, a comprehensive review of previously proposed designs has also been made and compared with current work.

A Compact Dual-Band Slot Antenna With Horizontally Polarized Omnidirectional Radiation

A dual-band horizontally polarized omnidirectional antenna for WiFi applications is proposed in this letter, which consists of a 3-D radiation slot on a metal box and three folded patches inside. The 3-D slot is formed by connecting two trapezoid slots at top and bottom of the box with a rectangle slot at the vertical side. Then, the radiation slot is excited by a folded patch connected to the feed line and produces two resonances at 2.45 and 5.5 GHz. With the help of two parasitic patches beside the excited patch, the higher frequency band is broadened. Measured results show that the antenna has two 10 dB return loss operating bandwidths of 5.32% and 20.56%. Moreover, the measured out-of-roundness for the horizontal radiation pattern is less than 2.4 dB in lower frequency band and that of higher frequency band is less than 5.3 dB. Besides, the antenna maintains a compact size of only 22 mm × 10 mm × 25 mm (0.18 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.08 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.20 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> , where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the wavelength of the lowest operating frequency), with the gain about 2 dBi and the cross-polarization ratio greater than 20 dB in the entire band.

Single‐fed dual wideband filtenna for 4G / 5G mobile applications

This article presents a single-fed single-layer dual-band slotted antenna which has the ability to simultaneously operate at microwave and millimeter-wave (MMW) frequency bands. It consists of a rectangular slotted ground plane, double cascaded tuning stubs, and embedded MMW element of L-shape inside the slotted ground. Ultra-wideband bandstop filter (BSF) is inserted at the feeding for isolating the two operational bands. The BSF consists of 3-open circuited stubs and in-line coupled line section. For demonstration, a design prototype of the complete integrated filtenna is fabricated and measured. Good agreements between simulated and measured results are observed. The proposed filtenna operates at 5.2 and 28 GHz with impedance bandwidth (15.23% and 17.03%) and the gain reaches (4.09 and 6.18 dBi).

Circularly Polarized Dual Band Dual Slot Antenna for WLAN, Wi-MAX and Wi-Fi Applications

In the last 15 years, the growth in the modern wireless communication systems has motivated enlarged exploration on inexpensive circularly polarized dual band slot antennas. A simple circularly polarized dual band dual slot antenna for WLAN, Wi-MAX and Wi-Fi applications is designed and analyzed. The proposed CP dual band antenna contains a radiating rectangular patch with two slots on low cost FR4-substrate having thickness of 1.6 mm. The CP dual band antenna is capable of resonating between 3.35 to 3.9 GHz and 4.8 to 6 GHz with S11 below −11 dB value. The proposed antenna exhibits the axial ratio value less than 3 dB in the two bands. This antenna utilizes single offset microstrip line feed and does not require any complicated phase shift network to provide 90° excitation phase difference. Hence this antenna can be used to form larger arrays to achieve higher gain. The antenna performance is significantly affected by the dimensions of the slots. The projected antenna is optimized using the ansoft HFSS. The antenna is fabricated to test the performance. The antenna exhibits adequate gain at the two bands. There is reasonable agreement between the simulated results and measured values.

5G dual-band slotted SIW array antenna

A dual-band slotted substrate-integrated waveguide four-element array antenna for the 5G communication system is presented in this manuscript. Two longitudinal slots are responsible for generating frequency bands of 28 and 38 GHz. The proposed antenna is designed on the substrate duroid 5880/Rogers having a loss tangent and dielectric constant of 0.003 and 2.2, respectively. The developed single-element design at 28 GHz provides 6.35 dBi gain, while at 38 GHz it provides 7.3 dBi gain and the simulation is carried out with CST Microwave Studio, 2018. To accomplish high gain, an optimized four-element array antenna is designed with a parallel feeding network on the same substrate that covers 28 GHz (27.6–28.1 GHz) and 38 GHz band (37.9–38.69 GHz). The designed antenna array attains the radiation efficiency of 88.08% with 12.7 dBi gain at 28 GHz and the efficiency of 84.44% with 15.5 dBi gain at 38 GHz band.

Dual-band pattern reconfigurable antenna using electromagnetic band-gap structure

A pattern reconfigurable antenna offers diverse pattern configurations and beam steering to cater the congested signal environment problem while maintaining the performances and operating frequency, as well as increasing the signal and data security. The pattern reconfigurable antenna using EBG structure is presented in this paper for beam-steering configurations. Most of the previous works proposed the PIN diode on the radiating patches, which caused the degradation of its performances. In this work, the structure offers good efficiency as the RF switches are not embedded to the radiating patches. A dual-band slotted pattern reconfigurable antenna using EBG structure is designed and analyzed. The EBG patches are located at the right and left of the radiating edge of the antenna. The EBG is designed so that its surface wave of band gap covers the radiation of the antenna. As a result, the surface waves excited by the patch antenna are prohibited from propagating by the EBG and caused the radiation pattern to be tilted to another side. The operating frequency of the proposed antenna is 2.45 GHz and 5.8 GHz for the dual-band antenna. The proposed antenna is capable of having beam shifting at three different angles (0°, +26°, and −26°).

A low rcs compact circularly polarized dual band slot antenna loaded with SRR and CSRR for satellite applications

ABSTRACT In this work, a low radar cross-section (RCS) dual-band with one band circularly polarised (CP) slot antenna consisting of an L-shaped metallic strip along with a combination of Split Ring Resonator (SRR) and complementary SRR (CSRR) is proposed. In the dual-band, one wideband operation is obtained by creating a wide slot in the ground plane of the antenna and a narrow band is achieved by loading the antenna with a combination of SRR-CSRR. The proposed antenna achieves impedance bandwidth of 1.5 to 3.26 GHz and 3.6 to 4.1 GHz. The proposed design has 3-dB axial ratio bandwidth (ARBW) of 2.5 to 3 GHz and the peak gain of the antenna is 4.2 and 3.3 dBi in the respective bands. The proposed antenna exhibits significant RCS reduction in the wideband of 4.7 to 18 GHz and peak RCS reduction of 26 dB is achieved at 11.3 GHz. Also, the sense of polarisation of the proposed antenna can be changed by 90° rotating the L-shaped metallic strip with reference to the slot in the ground plane.

A Dual Band Slotted Circular Microstrip Patch Antenna for Bluetooth and Commercial WLAN Applications

In this paper, a simple, low-cost and compact printed dual band slotted circular microstrip antenna with multiple slots and defected ground is proposed for Bluetooth and ITU10 SHF frequency. Dual-band operating frequencies 2.45 GHz (Bluetooth) and 4.25 GHz (WLAN) are obtained by using a slot insert in the circular radiating patch and a fractal rectangular ground patch. The proposed fabricated on a low-cost FR4 substrate having dimensions 45(Lsub)×45(Wsub)×1.6(Hsub) mm3 and fed by printed 50ohm microstrip feed line. The proposed antenna is designed and simulated using HFSS software. The antenna structure is fabricated and tested. Antenna measured S11 ≤ -10 dB at 2.45 GHz and 4.25 GHz.

Miniaturized dual‐band slot antenna design for GPS, amateur radio and WLAN applications

In this article, miniaturization of dual-band slot antenna design for GPS, WLAN and amateur radio applications is presented. The proposed dual-band miniaturized antenna is achieved using slits, rectangular split ring and metallic strips fed by 50 Ω microstrip feed. The first resonant frequency is achieved by loading reference antenna with eight slits that is antenna 1 and the second resonant frequency is achieved by loading with one center slits and rectangular split ring that is antenna 2. Dual-band antenna is achieved by loading reference slot antenna with nine slits and rectangular split ring which resonates at frequency of 1.52 and 3.03 GHz respectively. As a result, it is achieved 53.79% reduction in first band resonant frequency with 76.07% improvement in −10 dB bandwidth and 7.90% reduction in second band resonant frequency compared to reference slot antenna. Further, this dual-band antenna is miniaturized by metallic strips which are placed on the bottom of the substrate. This results in 61.39% reduction in first band resonant frequency with 32.07% improvement in −10 dB bandwidth and 26.13% reduction in second band resonant frequency in comparison with reference slot antenna topology.

Design of Integrated Duplexing and Multi-Band Filtering Slot Antennas

In this paper, a duplexing antenna and two multi-band filtering antennas using resonator loaded slot are presented. The loaded slot can be flexibly designed as a dual-band or a tri-band antenna by changing the number of the loaded resonator. The operating frequencies of the slot antenna can be easily controlled through tuning the lengths and positions of the loaded elements. By integrating the multi-band antenna and the multi-mode resonator, duplexing and filtering antennas can be realized. The duplexing antenna consists of two single-mode resonators, a dual-mode stub-loaded resonator as the junction resonator and a dual-band slot antenna. The dual-band and tri-band filtering antennas each contains a dual-mode resonator or a tri-mode resonator, radiating through resonator loaded slot antenna. Since the slot is the only radiation element, all the operating bands of the three antennas show good bi-directional radiation patterns. For validation, all of the antennas are designed, manufactured and measured.

Frequency reconfigurable slot antenna using metasurface for cognitive radio applications

A dual-port antenna system designed for cognitive radio applications is presented in this study. The structure comprises of an ultra-wideband (UWB) sensing antenna and a reconfigurable communicating antenna. The former is a stepped slot structure with an offset feed, which covers the whole UWB frequency band from 3 to 10.6 GHz, whereas the latter is a dual-band slot antenna (DBSA) fed with a fork-shaped microstrip-line feed and loaded with two identical layers of meandered metasurfaces (MSs). Frequency agility is realised by rotating the MS layers for the DBSA antenna. The dual-band communicating antenna has three switchable states with tuning ranges of 28 and 45% in the lower- and upper-frequency bands, respectively. The degree of isolation and gain in all three states are appreciable. The proposed structure is fabricated and measured, which has a good agreement with the simulated results.

Polarization Reconfigurable Dual-Band Rectangular Slot Antenna

Abstract A novel dual-band rectangular slot antenna is presented for dual-sense reconfigurable polarization. A W-shaped microstrip feedline and two rectangular parasitic patches are used to obtain dual-band circular polarization. Further, the feedline is modified so that the senses of polarization at the two bands are opposite. By introducing PIN-diodes in the feed lines, polarization can be switched among left-hand circular polarization (LHCP), right-hand circular polarization (RHCP), and linear polarization (LP). A prototype dual-band dual-sense antenna with f01 = 1.9 GHz and f02 = 3.45 GHz is fabricated in a 1.6 mm thick FR4 substrate. The measured circular polarized bandwidths are more than 7.6 % for the lower band and 5 % for the upper band.

Design and optimization of a dual-band slotted microstrip patch antenna using Differential Evolution Algorithm with improved cross polarization characteristics for wireless applications

ABSTRACTThis work presents a rectangular microstrip-line-fed patch antenna for Long Term Evolution, Universal Mobile Telecommunication Systems, Local Area Network, Bluetooth, Industrial, Scientific and Medical, Wireless Broadband, Worldwide Interoperability for Microwave Access, International Mobile Telecommunication, Radio Frequency Identification and Wireless Fidelity applications. The overall dimensions of antenna are 70 × 70 mm2. The antenna consists of a slotted radiating patch and defected ground structure, which is used to achieve dual-band frequency characteristics with appreciable bandwidth satisfying several communication standards simultaneously. Differential Evolution (DE) Algorithm is enforced in this work for achieving the best antenna geometrical design parameters and to obtain the desired results. The proposed antenna covers dual-frequency bands viz. 2.34–2.68 and 5.28–6.32 GHz with their resonating frequencies at 2.53 and 5.77 GHz, respectively. Further, an improvement in cross polarization discrimination of 15.4 dB for E plane and 9 dB for H plane is observed using DE algorithm. The fabrication and measurement of proposed antenna was carried out to verify the simulation results in the succeeding sections.

Brain Storm Optimization for Electromagnetic Applications: Continuous and Discrete

Brain storm optimization (BSO) is a swarm intelligence optimization algorithm inspired by the collective behavior of human beings in solving problems. This paper provides a conceptual overview and detailed explanation of the BSO algorithm. For the first time, the effectiveness of BSO in electromagnetic applications is demonstrated using a Yagi–Uda antenna design and a Luneburg lens antenna design, and this effectiveness is further validated via optimization, prototyping, and measurement of a dual-band slotted patch antenna design. In addition, a novel binary version of BSO (BBSO) for optimizing discrete problems is proposed, and the process of transforming the concept of BSO into a binary language is discussed in detail. A method for selecting algorithm parameter values for BBSO is shown. Finally, BBSO is applied successfully to an array thinning example and a pixelated patch antenna design.

High gain dual band slot antenna loaded with frequency selective surface for WLAN/fixed wireless communication

AbstractThis study shows the gain enhancement achieved through dual band slot antenna incorporated with dual band frequency selective surface. In order to do this, at first, a dual band novel 7 × 7 spanner shape FSS is designed, and its operations is analyzed by using the ray tracing method. The second step involves designing the dual band slot antenna resonating at 3.53 and 6.2 GHz, respectively. The designed FSS is then used as superstrate on the slot antenna in which cavity resonance occurs due to multiple reflections and leaked out waves, thereby enhancing antenna's gain significantly on both the bands. Further, the overall gain of slot antenna with the superstrate is achieved as 13.00 and 13.92 dBi on the 2 respective resonant frequencies; this in turn results in a gain enhancement of 8.0 and 6.82 dB at 3.53 and 6.2 GHz, respectively. The measured results coincide verifying the results of the simulated structure. This is followed by a parametric analysis for air gap between FSS and the radiating antennas, which in turn have been designed for wireless and satellite communications.